The present invention resides in a flywheel energy accumulator with a vertical shaft and passive superconductive magnetic axial bearings and an electric motor/generator including a rotor coupled mechanically to several flywheels and a stationary armature with a vacuum housing in which the flywheels are disposed in spaced relationship.
Superconductive magnetic bearings are particularly suitable for supporting relatively large flywheel masses for storing energy with relatively small losses. The superconductive bearings do not require any controls as they are self stabilizing. With flywheel energy accumulators, electric energy is converted in a motor/generator unit to kinetic energy which is stored in a flywheel disc. It is important that the losses during the storing of the energy are minimized so as to retain as much as possible of the stored energy. For this reason, the rotor of the system is supported without mechanical contacts by superconductive magnets as pointed out earlier.
U.S. Pat. No. 6,043,577 discloses a flywheel energy accumulator with a vertical shaft and passive superconductive magnetic axial bearings. However, the energy storage capability of this accumulator, which cannot be easily geometrically enlarged, is insufficient for electrical power networks or even for use in motor vehicles.
It is the object of the present invention to provide an improved flywheel energy accummulator with an energy storage capacity and a performance in the range of 1 to 5 MW and 50 to 150 kwh.